1. Field of the Invention
The present invention relates to an optical element, and in particular relates to a wafer-level optical element, image capture lens structure and manufacturing thereof.
2. Description of the Related Art
In recent years, image capture apparatuses, such as mobile phones with a photographing function and digital cameras have become popular due to employment of solid-state image capture devices, such as CCD (charged coupled device) type image sensors, CMOS (complementary metal oxide semiconductor) type image sensors and the like, which are capable of meeting demands for higher performance and miniaturization. In such image capture devices, taking a picture is performed by forming an object image on a detecting surface of the image capture device so as to capture an image, and then the image data is read (i.e. output).
In the image capture apparatus, the optical elements include refractive components such as lenses and diffractive and/or refractive micro-optical components for influencing an optical beam in a pre-defined manner.
When optical elements are produced by replication, there is often a basic configuration involving a substrate and replication material on a surface thereof. The replication material can be shaped and hardened in the course of a replication process.
Conventionally, the optical element includes effective areas and non-effective areas, wherein both effective and non-effective areas are very smooth, as like a mirror. Unfortunately, the smooth non-effective area reflects large angles or any unnecessary light to cause stray-light of images, wherein stray-light significantly impacts image quality. In addition, when an optical element is bonded to another optical element, the bonding adhesive usually overflows and closes the optical path (effective area). The leaked adhesive also reflects the unnecessary light resulting in image destruction.
FIGS. 1A and 1B are cross-sectional views illustrating a conventional structure of a wafer-level optical element. As shown in FIG. 1A, an optical element 10 is composed of a substrate 12 and lens 14. The lens 14 is indicated by two areas including non-effective area 142 and effective area 144. As discussed above, both effective and non-effective areas are smooth so that unnecessary light is reflected to cause stray-light of image. Additionally, referring to FIG. 1B, an optical element is bonded to another optical element to form a wafer level image capture lens by using a spacer 16 and an adhesive 18, wherein the adhesive usually overflow to close or contact the non-effective area 142. Similarly, the unnecessary light also can be reflected by the leaked adhesive 20. The image sensor, such as a CMOS or CCD, thus usually catches the reflected light, resulting in decrease of image quality.
Thus, a novel manufacturing method and an optical structure are required to mitigate the previously mentioned problems.